Furnace section for kiln



Nov. 23, 1965 B. c. MILLER FURNACE SECTION FOR KILN 2 Sheets-Sheet 1 Filed July 16, 1963 INVENTOR. BOYD C. M\ LLE-R.

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+wg1 AT TOE/VE VS MN ON 8 .w mm Q Q U MW mama Nov. 23, 1965 B. c. MILLER FURNACE SECTION FOR KILN Filed July 16, 1963 2 Sheets-Sheet 2 INVENTOR. BOYB C. VMLLER ZMM W United States Patent 3,219,328 FURNACE SECTIQN FOR KILN Boyd C. Miller, 1123 W. Henderson St., Salisbury, N.C. Filed July 16, 1963, Ser. No. 295,366 4 Claims. (Cl. 263-28) This invention relates generally to an improved furnace section for heat-treating any desired type of ware in either a continuous or a periodic type kiln. While the present invention is disclosed in connection with a tunneltype kiln which is normally provided with successive drying, preheating, furnace, fast-cooling, annealing, and finalcooling sections through which the ware to be treated is carried on a train of kiln cars which are movable along suitable tracks extending through the kiln, the invention may also be utilized with periodic or shuttle type kilns.

It is a primary object of the present invention to provide an improved furnace section which economically provides self-circulating heat within the furnace section and wherein the heating means uniformly distributes the heated gases over and through the ware and prevents discoloration of the ware due to excessive heat in certain locations.

It is a more specific object of the present invention to provide an improved furnace section of the type described in which a longitudinally extending baffle wall is spaced inwardly from each of the sidewalls to form combustion chambers along opposite sides of the furnace section and at opposite sides of the ware, and in which a plurality of closely spaced low velocity fuel burners are supported in vertical positions along each side wall so that the heated gases are directed upwardly by the bafile walls and along the side walls to the ceiling where they are uniformly circulated downwardly through the ware on the kiln cars and back beneath the bafille walls at each side of the furnace section. Since the low velocity fuel burners are directed upwardly, the baffle walls protect the ware from flame impingement and consequent discoloration of the ware.

It is another specific object of the present invention to provide an improved furnace section of the type described in which the vertically directed fuel burners are supported in inwardly projecting shelf portions of each side wall and are spaced sufficiently close together that they emit a continuous ribbon of heated gases upwardly from opposite sides of the furnace section.

Some of the objects of the invention having been stated, other objects will appear as the description proceeds, when taken in connection with the accompanying drawings, in which:

FIGURE 1 is a sectional plan View of the trailing end portion of the preheating section and the leading end portion of the furnace section of the kiln;

FIGURE 2 is a side elevation of that portion of the kiln shown in FIGURE 1 with the central portion broken away to illustrate a portion of the interior;

FIGURE 3 is an enlarged vertical sectional view through the furnace section of the kiln, taken substantially along the line 3-3 in FIGURE 1, and showing a kiln car in cross-section with a plurality of pipes shown in dotted lines and supported on the kiln car in position to be heat treated;

FIGURE 4 is an enlarged elevation of the lower righthand portion of FIGURE 3; and

FIGURE 5 is a vertical sectional View taken substantially along the line 55 in FIGURE 4, and illustrating the close spacing of a group of the fuel burner units.

Referring particularly to FIGURE 2, it will be noted that the preheating section indicated at A and the furnace section indicated at B are interconnected and form only a portion of the elongated tunnel-type kiln which also includes other successive sections through which the ware travels as it is treated. The kiln is normally constructed of blocks of refractory material and is supported on a foundation slab 10 which normally extends from one end of the kiln to the other.

Stepped support pillars 11 and 12 (FIGURE 3) are spaced at predetermined intervals along the foundation slab 10 and beneath both the preheating and furnace sections A and B to form the main support for opposite side walls 13 and 14. The stepped pillars 11 and 12 are usually formed of refractory blocks and support suitable floor beams 15 which extend therethrough. The medial portions of the floor beams 15 are suitably supported on the upper ends of central support pillars 16 which are supported on the foundation slab 10 and between each of the stepped pillars 11 and 12.

The lower portions of each of the side walls 13 and 14 are provided with respective shelf portions 13a and 14a which extend inwardly thereof and which are supported on the stepped pillars 11 and 12 respectively (FIGURE 3). The shelf portions 13a and 14a extend longitudinally of both the preheating and furnace sections A and B, as shown in FIGURE 1.

The upper ends of the side walls 13 and 14 are connected by a curved roof 20. The lower ends of buckstays 21 and 22 are suitably connected to opposite ends of the floor beams 15 and extend upwardly beside the respective side walls 13 and 14, their upper ends being connected together by suitable tie rods 23 which pass above the roof 20 of the kiln.

Suitable spaced apart car supporting rails 25 extend longitudinally of the kiln and are supported on the transverse fioor beams 15. Suitable ware supporting cars C are supported for continuous movement along the rails 25 to move the ware to be treated through the kiln at a predetermined speed. As shown in FIGURE 3, each of the cars C is provided with a lower frame 30 that is supported for sliding movement along the rails 25, however, it is to be understood that the car C could be provided with wheels, if desired. The lower frame 39 supports a solid bed of refractory material 31 and a ware supporting platform 32 which is formed of spaced refractory blocks forming passageways through which the heated gases may circulate, in a manner to be presently described.

The upper level of the solid bed 31 of the car C is substantiall level with the upper levels of the adjacentshoulder portions 13a and 14a (FIGURE 3) and they collectively form a floor for the kiln to prevent the heated gases from escaping. In the present instance, a plurality of pipes P, indicated in dotted lines in FIGURE 3, are supported on pipe rings 33 which are in turn supported on the upper surface of the platform 32 of the car C.

As is best shown in FIGURE 1, the side walls 13 and 14 are not as thick in the preheating section A as they are in the furnace section B and these two sections are divided by internal section piers 35 and 36 which extend upwardly from the respective shelf portions 13a and 14a and along the side walls 13 and 14 to the roof 29. These section piers 3S and 36 serve to prevent the rapid transfer of heat from the furnace section to the preheating section and allow the furnace section to be maintained at a much higher temperature than the preheating section.

In the furnace section B, suitable bafile walls 43 and 44 are spaced from the respective side walls 13 and 14 and extend longitudinally therealong to define combustion chambers therebetween. The baflie walls 43 and 44.

are preferably formed of built-up hollow blocks which are formed of refractory material and the lower edges of the bafile walls are supported in spaced relation above the upper edges of the shelf portions 13a and 14a of the side walls and on the upper end of respective baffle wall piers 45 and 46. As shown in FIGURE 1, these bafile wall piers 45 and 46 are spaced along opposite sides of the furnace section B and their lower ends are supported on the shelf portions 13a and 14a. The leading ends of the baffle walls 43 and 44 are supported in the respective section piers 35 and 36 and the baflie walls 43 and 44 are connected to the respective side walls 13 and 14 at spaced intervals by respective connector walls 43a and 44a (FIGURE 1).

The lower portions of the side walls 13 and 14 are provided with respective clean-out ports 53 and 54 which are spaced closer together in the furnace section B than in the pre-heatiug section A (FIGURE 2). Each of the cleanout ports is provided with a cast iron sleeve which provides a peephole for periodic inspection of the heater means.

Fuel burners indicated at 60 are supported in vertical positions in both sections A and B to heat the same. In the present instance, the burners 60 are connected to suitable gas and air lines 61 and 62 respectively (FIG- URE 4), however, it is to be understood that they could be blower-type oil burners. As is clearly shown in FIG- URE 1, there are many more burners 60 in the furnace section B than there are in the pre-heating section A and the baffle walls 44 and 45 do not extend into the preheating section A.

In the furnace section B, the burners 60 are closely spaced in groups along each of the side walls 13 and 14 and in the combustion chambers between the side walls and the baffie walls 43 and 44. There is a group of four of the burners 60 between each of the floor beams 15 and the groups of burners are closely spaced together. As shown in FIGURE 5, the burners 60 are supported in a vertical position in the shelf portions 13a and 14a and as close together as possible. In the present instance, there is only one fire brick between each of the burners 60, shown in FIGURE 5, and their emitted flames, shown in dash-dot lines, overlap to send up a continuous ribbon of uniformly heat gases.

As has heretofore been described, the kiln cars C are moved along the track in a continuous manner, that is, one car is pushed by the next succeeding car. As the cars move from left to right in FIGURES 1 and 2, they first pass through the preheater section A Where the smaller number of burners 60 gradually raise the temperature as the cars advance toward the furnace section. As the cars move into the furnace section B where the larger number of burners 60 are disposed closely adjacent to each other, the heated gases rise from the bafile walls 43 and 44 and against the roof 20 to be uniformly circulated in the manner indicated by the arrows in FIGURE 3.

Thus, the heated gases pass downwardly through and around the pipes P, outwardly through the passageways between and through the blocks of the car platform 32, beneath the lower edges of the baffie walls 43, 44 and again upwardly in the combustion chambers. As the car C is moved slowly through the furnace section B, the temperature is maintained at approximately 2200 F.

In the present improved furnace section, the heated gases continuously rise from the combustion chambers at each side of the furnace section and provide a self-circulating heating system within the furnace section which is uniformly distributed over the surfaces of the articles to be treated. Since the burners 60 are supported in a vertical position, their flames do not directly engage the ware on the cars to thereby prevent discoloration of the ware. With the close spacing of the low velocity fuel burners, a uniform high temperature is maintained in the furnace section and this uniform high temperature has not been heretofore possible with high velocity fuel burners spaced further apart.

In the drawings and specification there has been set forth a preferred embodiment of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention being defined in the claims.

I claim:

1. An improved furnace section for a kiln having ware positioned therein to be heat-treated, said furnace section comprising (a) spaced apart vertically extending side walls,

(b) a roof connecting said side walls,

(c) a plurality of groups of upwardly directed fuel burners along each of said walls, the burners in each group being spaced apart by a single fire brick and adapted to emit overlapping flames,

(d) baffle walls spaced inwardly of said fuel burners and defining longitudinally extending combustion chambers between said side Walls and said baffle walls and adapted to uniformly circulate the heated gases through the ware positioned between the longitudinally extending combustion chambers, the upper ends of said baffle walls terminating below said roof, and the lower ends of said baflle walls terminating above the level of said fuel burners to provide return air passages into the combustion chambers, and,

(e) connector walls extending between the bafile walls and their respective side walls in perpendicular re lation thereto; said connector walls also extending between certain of said groups of fuel burners and transversely of said combustion chambers to define a plurality of combustion chambers on each side of the furnace section.

2. An improved furnace section for a tunnel-type kiln having track means extending therethrough, a train of kiln cars mounted for movement along said track means, and ware positioned on said kiln cars to be heat-treated, said furnace section comprising (a) spaced apart vertically extending side walls,

(b) a roof connecting said side walls,

(0) a plurality of groups of upwardly directed fuel burners along each of said side walls, the burners in each group being spaced apart by a single fire brick and adapted to emit overlapping flames,

(d) bafile walls spaced inwardly of said fuel burners and defining longitudinally extending combustion chambers between said side walls and said baflle walls and adapted to uniformly circulate the heated gases through the ware on the kiln cars as they pass therethrough, the upper ends of said baffle walls terminating substantially half-Way up said side walls and at a level of substantially half the height of the ware on the kiln cars, and the lower ends of said bafile walls terminating above the level of said fuel burners to provide return air passages into the combustion chambers, and,

(e) connector walls extending between the bafiie walls and their respective side walls in perpendicular relation thereto; said connector walls also extending between certain of said groups of fuel burners and transversely of said combustion chambers to define a plurality of combustion chambers on each side of the furnace section.

3. An improved furnace section for a tunnel-type kiln having track means extending therethrough, a train of kiln cars mounted for movement along said track means, each of said kiln cars having a solid bed and a ware supporting platform with air circulating passageways therein, and ware positioned on the platforms of said kiln cars to be heat-treated, said furnace section comprising (a) spaced apart vertically extending side walls,

(b) a roof connecting said side walls,

(0) inwardly projecting shelf portions formed along the lower portions of each side wall, the upper levels of said shelf portions terminating at substantially the same level as the upper level of the solid bed of said kiln cars,

6 (d) a plurality of groups of upwardly directed fuel spaced apart by a single fire brick and adapted to burners supported in said self portions along each emit overlapping flames, of said side walls, the burners in each group being (e) bafile walls spaced inwardly of said fuel burners spaced apart by a single fire brick and adapted to and defining longitudinally extending combustion emit overlapping flames, 5 chambers between said side walls and said baffle (e) baffle walls spaced inwardly of said fuel burners walls and adapted to uniformly circulate the heated and defining longitudinally extending combustion gases through the Ware supported on the kiln cars chambers between said side walls and said battle as they pass therethrough, the upper ends of said walls and adapted to uniformly circulate the heated baffle walls terminating below said roof, and the gases through the ware supported on the kiln cars 10 lower ends of said bafile walls terminating above as they pass therethrough, the upper ends of said the level of said shelf portions to provide return bafile walls terminating below said roof, and the air passages into the combustion chambers, and lower ends of said baffle walls terminating above the (f) a plurality of spaced baffle wall piers positioned level of said shelf portions to provide return air on said shelf portions and extending upwardly therepassages into the combustion chambers, and, from, the upper ends of said bafile wall piers sup- (f) connector Walls extending between the baflle walls portingly engaging the lower ends of said baflle and their respective side walls in perpendicular rewalls, and, lation thereto; said connector walls also extending (g) connector walls extending between the bafile walls between certain of said groups of fuel burners and and their respective side Walls in perpendicular relatransversely of said combustion chambers to define tion thereto; said connector walls also extending bea plurality of combustion chambers on each side of tween certain of said groups of fuel burners and the furnace section. transversely of said combustion chambers to define 4. An improved furnace section for a tunnel-type kiln a plurality of combustion chambers on each side having track means extending therethrough, a train of of the furnace section.

kiln cars mounted for movement along said track means,

each of said kiln cars having a solid bed and a ware References Cited by the Examiner supporting platform with air circulating passageways UNITED STATES PATENTS therein, and Ware positioned on the platforms of said 1688 393 10/1928 Manker 263 28 kiln cars to be heat-treated, said furnace section com- 3 1988837 1/1935 Dresslfir 263 28 Pnsmg 0 2,509,209 5/1950 Castle 263-28 (a) spaced apart vertically extending side Walls, 2 540 806 2/1951 Berger (b) a roof connecting said side walls, (c) inwardly projecting shelf portions formed along 293060O 3/1960 Boden 263 28 the lower portions of each side wall, the upper levels FOREIGN PATENTS of said shelf portions terminating at substantially 668 707 11/1929 France 2:82:31 lgerealrsas the upper level of the solid bed 647,053 12/1950 Great Britain. ((1) a plurality of groups of upwardly directed fuel burners supported in said shelf portions along each WILLIAM ODEA Actmg Prlmary Exammer of said side walls, the burners in each group being CHARLES SUKALO, Examiner. 

1. AN IMPROVED FURNACE SECTION FOR A KILN HAVING WARE POSITIONED THEREIN TO BE HEAT-TREATED, SAID FURNACE SECTION COMPRISING (A) SPACED APART VERTICALLY EXTENDNG SIDE WALLS, (B) A ROOF CONNECTING SAID SIDE WALLS, (C) A PLURALITY OF GROUPS OF UPWARDLY DIRECTED FUEL BURNERS ALONG EACH OF SAID WALLS, THE BURNERS IN EACH GROUP BEING SPACED APART BY A SINGLE FIRE BRICK AND ADAPTED TO EMIT OVERLAPPING FLAMES, (D) BAFFLE WALLS SPACED INWARDLY OF SAID FUEL BURNERS AND DEFINING LONGITUDINALLY EXTENDING COMBUSTION CHAMBERS BETWEEN SAID SIDE WALLS AND SAID BAFFLE WALLS AND ADAPTED TO UNIFORMLY CIRCULATE THE HEATED GASES THROUGH THE WARE POSITIONED BETWEEN THE LONGITUDINALLY EXTENDING COMBUSTION CHAMBERS, THE UPPER ENDS OF SAID BAFFLE WALLS TERMINATING BELOW SAID ROOF, AND THE LOWER ENDS OF SAID BAFFLE WALLS TERMINATING ABOVE THE LEVEL OF SAID FUEL BURNERS TO PROVIDE RETURN AIR PASSAGES INTO THE COMBUSTION CHAMBERS, AND, (E) CONNECTOR WALLS EXTENDING BETWEEN THE BAFFLE WALLS AND THEIR RESPECTIVE SIDE WALLS IN PERPENDICULAR RELATION THERETO; SAID CONNECTOR WALLS ALSO EXTENDING BETWEEN CERTAIN OF SAID GROUPS OF FUEL BURNERS AND TRANSVERSELY OF SAID COMBUSTION CHAMBERS TO DEFINE A PLURALITY OF COMBUSTION CHAMBERS ON EACH SIDE OF THE FURNACE SECTION. 